From Polar Bear Science
Posted on February 24, 2021 |
The ‘State of the Polar Bear Report 2020’ is now accessible. Overlook hand-wringing about what would possibly occur fifty years from now – have a good time the fabulous information that polar bears had one more good 12 months.
Press launch from the World Warming Coverage Discussion board:
Obtain the report right here.
Crockford, S.J. 2021. The State of the Polar Bear Report 2020. World Warming Coverage Basis Report 48, London.
London, 27 February: A outstanding Canadian zoologist says that Fb’s info is gravely outdated and 2020 was one other good 12 months for polar bears.
Within the State of the Polar Bear Report 2020, printed by the World Warming Coverage Basis (GWPF) on Worldwide Polar Bear Day, zoologist Dr. Susan Crockford explains that whereas the local weather change narrative insists that polar bear populations are declining as a result of diminished sea ice, the scientific literature doesn’t help such a conclusion.
Crockford clarifies that the IUCN’s 2015 Purple Record evaluation for polar bears, which Fb makes use of as an authority for ‘truth checking’, is critically outdated. New and compelling proof reveals bears that in areas with profound summer season ice loss are doing effectively.
Included in that proof are survey outcomes for eight of the 19 polar bear subpopulations, solely two of which confirmed insignificant declines after very modest ice loss. The remaining had been both steady or growing, and a few regardless of main reductions in sea ice. Consequently, the worldwide inhabitants measurement is now nearly 30,000 – up from about 26,000 in 2015.
Dr. Crockford factors out that in 2020, though summer season sea ice declined to the second lowest ranges since 1979, there have been no studies of widespread hunger of bears, acts of cannibalism, or drowning deaths which may counsel bears had been having hassle surviving the ice-free season.
As Crockford’s report reveals, plankton progress – the crucial well being measure of marine life within the Arctic – reached document highs in August 2020. Extra plankton (‘main productiveness’) as a result of much less summer season ice means extra fodder for the complete meals chain, together with polar bears. This explains why bears are thriving in areas such because the Barents Sea, which have seen diminished ranges of sea ice.
Dr. Crockford notes that, paradoxically, polar bears in Western Hudson Bay skilled glorious ice circumstances for the fourth 12 months in a row in 2020. Bears had been fats and wholesome after they arrived on shore for the summer season. Some spent as little as three months on shore – about one month much less time than most bears did within the 1980s and two months lower than bears did within the 1990s and 2000s.
Dr. Crockford explains that polar bears are extra versatile of their habitat necessities than consultants assumed and fewer summer season ice has to this point been useful slightly than detrimental.
“Polar bears proceed to be described as ‘canaries within the coal mine’ for the consequences of human-caused local weather change, however the proof reveals they’re removed from being a highly-sensitive indicator species. It’s not a fable: 2020 seems to have been one other good 12 months for polar bears.”
- Outcomes of three new polar bear inhabitants surveys had been printed in 2020 and all had been discovered to be both steady or growing.
- Southern Beaufort polar bear numbers had been discovered to have been steady since 2010, not diminished as assumed and the official estimate stays about 907.
- M’Clintock Channel polar bear numbers greater than doubled from 284 in 2000 to 716 in 2016, as a result of diminished looking and improved habitat high quality (much less multiyear ice).
- Gulf of Boothia numbers had been discovered to be steady, with an estimate of 1525 bears in 2017; physique situation elevated between examine durations and thus confirmed ‘good potential for progress’.
- At current, the official IUCN Purple Record international inhabitants estimate, accomplished in 2015, is 22,000-31,000 (common about 26,000) however surveys performed since then, together with these made public in 2020, would elevate that common to nearly 30,000. There was no sustained statistically vital decline in any subpopulation.
- Experiences on surveys in Viscount Melville (accomplished 2016) and Davis Strait (accomplished 2018) haven’t but been printed; completion of an East Greenland survey is anticipated in 2022.
- In 2020, Russian authorities introduced the first-ever aerial surveys of all 4 polar bear subpopulations (Chukchi, Laptev, Kara, and Barents Seas), to be undertaken between 2021 and 2023.
- Opposite to expectations, a brand new examine has proven that polar bear females within the Svalbard space of the Barents Sea had been in higher situation (i.e. fatter) in 2015 than they’d been within the 1990s and early 2000s, regardless of contending with the best decline in sea ice habitat of all Arctic areas.
- Major productiveness within the Arctic has elevated since 2002 due to longer ice-free durations (particularly within the Laptev, East Siberian, Kara, and Chukchi Seas but in addition within the Barents Sea and Hudson Bay), however hit data highs in 2020; extra fodder for the complete Arctic meals chain explains why polar bears, ringed and bearded seals, and walrus are thriving regardless of profound sea ice loss.
- In 2020, opposite to expectations, freeze-up of sea ice on Western Hudson Bay got here as early within the autumn because it did within the 1980s (for the fourth 12 months in a row) and sea-ice breakup in spring was additionally just like the 1980s; polar bears onshore had been in glorious situation. These circumstances got here regardless of summer season sea-ice extent throughout the complete Arctic being the second lowest since 1979. Knowledge collected since 2004 on weights of feminine polar bears in Western Hudson Bay have nonetheless not been printed; as a substitute, polar bear specialists have reworked commonplace physique situation knowledge collected 1985–2018 into a brand new metric for inhabitants well being they name ‘energetics’, which can’t be in contrast with earlier research. In the meantime, they proceed to quote decades-old uncooked knowledge from earlier research to help statements that lack of sea ice is inflicting declines in physique situation of grownup females, cub survival, and inhabitants measurement.
- Opposite to expectations, in Western Hudson Bay, many polar bears remained on the deteriorating sea ice for much longer than typical in summer season, and stayed ashore longer in fall after official freeze-up thresholds had been reached, calling into query the assumed relationship between sea-ice protection and polar bear behaviour and well being. Some bears that left the ice in late August after which returned earlier than late November would have spent solely three months onshore – about one month much less time than typical within the 1980s, and two months lower than within the 1990s and 2000s.
- There have been few drawback polar bear studies in 2020, aside from one deadly polar bear assault in August, in a campground close to Longyearbyen, Svalbard. Ryrkaypiy, Chukotka, which in 2019 was besieged by greater than 50 bears that had congregated to feed on walrus carcasses close by, prevented an analogous drawback in 2020 by posting guards across the city. The city of Churchill noticed the bottom variety of issues bears in years.
- In 2020, nearly all polar bear analysis was halted throughout the Arctic for the complete 12 months as a result of restrictions on journey and efforts to isolate weak northern communities from Covid-19.